Drivers of all types of vehicles are often unaware of the effects that drowsiness and distraction have on their own abilities for vehicle control. Humans in general, and particularly as drivers, are poor judges of their own performance capabilities. Typically, a driver's self-impression of his or her capabilities is better than actuality. Even persons who have basically good driving skills, will not perform uniformly at all times when behind the wheel of a vehicle. Furthermore, there are many times during driving trips that very little demand is placed on the driver with respect to execution of driving tasks. As a result, drivers are lulled into states of mind where little attention is being devoted to the driving task. Not surprisingly, driver inattention is a leading cause of vehicular collisions, and especially automotive collisions. According to a Nation Highway and Transportation Safety Administration (NHTSA) study of over two and one-half million tow-away crashes in a year's time, driver inattention is a primary cause of collisions that accounts for an estimated twenty-five to fifty-six percent of crashes. In that study, inattention was defined as having three components: visual distraction, mental distraction (looking without seeing) and drowsiness. Common crash types caused by inattention are: rear-end collisions, collisions at intersection, collisions while lane changing or merging, road departures, single vehicle crashes, and crashes that occur on low speed limit roadways.
Drowsy drivers are a well known phenomenon. At least one survey has indicated that fifty-seven percent of drivers polled had driven while drowsy in the previous year, and twenty-three percent had actually fallen asleep at the wheel. It is known that fatigue impairs driver performance, alertness and judgment. Collisions caused by drowsiness are a serious road safety problem, and fatigue has been estimated to be involved in as many as twenty-three percent of all crashes.
From a technological perspective, there is an ongoing and rapid increase of new information systems and functionalities that may be used within vehicles including mobile telephones, navigation aids, the internet, and other types of electronic services. The effect of mobile telephone use on drivers has been foremost in the public eye because of their widespread use, but sales of navigation aids and IT services are also growing fast. Mobile telephones alone have been estimated to have caused 300-1000 fatalities in one year's time in the United States, and this is projected to reach 4000 fatalities per year in 2004. Distractions such as handheld telephone use, sign reading, eating food, interaction with other passengers, observing objects and manipulating devices in-the vehicle have the potential for capturing a driver's attention in an excessive way and thus also compromising safety. It is especially important that driving safety not be compromised as these new types of services and activities become more common place in the driving environment.
Driver workload increases based on utilization of these new functionalities and technologies. In this context, “workload” should be understood to refer to how busy a person is and the amount of effort they need to perform required tasks. When a driver has many things to do and is experiencing high workload, a high attention demand is being made on the driver in that there is much to be done at the same time. Drivers often attend to things that are not related to driver control of the vehicle and are therefore technically irrelevant to the driving situation. These things are often called secondary tasks and are potential distracters from driver attention to primary driving tasks. A secondary task becomes a distraction (including visual-, auditory-, cognitive-, and biomechanical distractions) when the driver's attention is captured thereby to a degree that insufficient attention is left for the primary control tasks of driving. As a result, driving performance such as lane keeping and speed control are compromised as ultimately is safety.
Driving tasks and secondary tasks overlap in the sense that some secondary tasks are driving related as diagrammatically shown in FIG. 1. Two difficulties arise from this relationship between the driving and secondary tasks. First, it can be difficult to delineate which secondary task information is “irrelevant to the driving situation” and which is not; and second, certain driving related secondary tasks, for instance, looking for a street sign or planning a driving route may also compromise safety as graphically depicted in FIG. 1.
It should also be appreciated that the driver is often unaware of the effects of distraction on the driving task. Also, drivers cannot reliably determine when they are impaired by fatigue to the point of having a serious vigilance lapse or uncontrolled sleep attacks. The attention management systems outlined herein are intended to increase safety by assisting the driver in drowsy, distractive, and/or high workload situations.